Most fracturing processes use various chemicals in their process to recover gas and oil. For example, U.S. Pat. No. 8,733,439 uses CO2, but also used H2O2 (hydrogen peroxide) which, when used medically in small amounts, is considered a mild antiseptic, and can be used as a bleaching agent. Hydrogen peroxide can be used for certain industrial or environmental purposes as well, because it can provide the effects of bleaching without the potential damage of chlorine-based agents. Because this substance can be unstable in high concentrations, it must be used with care. In higher concentrations, it can create strong chemical reactions when it interacts with other agents, and it can damage the skin or eyes of persons working with it. The use in wells may contaminate underground water if there is seepage into ground water. This patent also uses other chemicals such as Fe, Co, Ni and similar chemicals.
Other processes also use various chemicals, particulate material, and other catalysts which can contaminate water sources such as wells and aquifers. These processes utilize a large amount of water which often is not or cannot be recycled because of the toxic chemicals contained therein.